Virginia's candidates for governor are bracing for abortion to emerge as a volatile and perhaps decisive issue as the final months of the 2005 campaign coincide with a national debate over President Bush's choice to replace Supreme Court Justice Sandra Day O'Connor.

Senior advisers for the Virginia candidates, along with the state's leading abortion rights activists and abortion opponents, say interest in whether a newly constituted court might overturn the 32-year-old decision legalizing abortion will energize a debate that has faded from prominence in Virginia elections.

Rumors persist that Chief Justice William H. Rehnquist, and perhaps even a third justice, could resign soon, giving Bush a chance to reshape the court.

"Clearly, this battle over nominees brings the life issue to the forefront, across the nation but more specifically where we have gubernatorial races," said Victoria Cobb, the executive director of the Family Foundation, which supports restrictions on abortion. The abortion debate is "being taken to the next level, knowing . . . that Roe v. Wade hangs in the balance."

Jatrice Martel Gaiter, the president and chief executive of Planned Parenthood of Metropolitan Washington, said the abortion issue will now "deeply influence" the Virginia governor's race.

"We are going to enter the battle," she promised. "We will not sit quietly and be run over by men and far-right conservatives who want to determine when and whether a woman should have a child."

A more conservative court could encourage Virginia's lawmakers -- among the nation's most aggressive when it comes to limiting abortion -- to pass more comprehensive restrictions. If the Supreme Court overturned Roe entirely, the issue would likely return to the capital, where legislatures and the new governor could decide whether to make abortions illegal.

Del. Robert G. Marshall (R-Prince William), the leading antiabortion crusader in the legislature, said he "will not let up" in his efforts to restrict and ultimately outlaw the procedure.

"I certainly would not miss this opportunity," he said.

Activists on both sides said that prospect makes the choice of a governor critical.

Lt. Gov. Timothy M. Kaine, the Democratic candidate, supports "reasonable restrictions" on abortion but believes in a woman's right to have one. Republican Jerry W. Kilgore says abortion should be allowed only in cases of rape or incest, or to save a mother's life. Sen. H. Russell Potts Jr. (R-Winchester), who is running for governor as an independent, has been a leading supporter of abortion rights in recent years.

None has responded to letters from Marshall asking whether they would sign or veto legislation outlawing abortion if the Supreme Court overturns Roe.

"They are trying to figure out ways with their consultants to finesse this," Marshall said. "There ain't no way to finesse this."

Not since 1989, when the Supreme Court opened the door to state regulation of abortion, has the issue played a major role in electing Virginia's governor. In that contest, then-Lt. Gov. L. Douglas Wilder (D) used a fear of new abortion restrictions to mobilize support for his candidacy.

In his book, "The Dynamic Dominion," top Republican strategist Frank B. Atkinson writes that the court's ruling in Webster v. Reproductive Health Services "suddenly energized the pro-choice activists in the summer of 1989, thereby transforming the dynamics of the Virginia campaign for governor."

Wilder won. In exit polls, 32 percent said their most important issue was abortion, dwarfing any other. Only 22 percent said education, 13 percent said taxes and 7 percent said transportation.

Since then, the issue has faded.

"The pro-choice people have lost ground in the last 15 years because people have not believed the right to choose is really threatened," said Larry J. Sabato, director of the University of Virginia's Center for Politics. "If Bush nominates strong conservatives for the Supreme Court, this issue will be back, front and center."

For months, all three candidates have focused on taxes, transportation, jobs, the environment and education. Now they are looking for ways to use abortion to their advantage.

Kilgore campaign aides said they believe Kaine is vulnerable to charges that he has flip-flopped.

While running for lieutenant governor in 2001, Kaine said he believed "very strongly that the current legal framework . . . is one that shouldn't be regulated overly by the Commonwealth of Virginia." That contrasts with Kaine's current tone, which emphasizes his "faith-based opposition" to abortion. Kaine, who is Roman Catholic, says his goal is reducing the number of abortions.

"Kaine has morphed from a straight-up, pro-choice candidate to one who is trying to hoodwink people into thinking he's pro-life," said Kilgore spokesman Tim Murtaugh.

Kaine advisers said an increased focus on abortion will hurt Kilgore because of what they described as the Republican's "extreme" position on the issue.

"He's made it very clear that he thinks women and doctors should be put behind bars, that it should be a criminal practice," Kaine spokeswoman Delacey Skinner said of Kilgore.

But Ann O'Hanlon, executive director of NARAL Pro-Choice Virginia and a former Washington Post reporter, said Kaine could lose abortion rights votes by accepting restrictions. "Tim's got to be very clear with voters that there are no further restrictions on abortion he would put on us," she said.

O'Hanlon said some abortion rights supporters could end up voting for Potts, who has repeatedly blocked abortion restrictions when they came up in the Senate Education and Health Committee, which he chairs.

Asked whether he would sign or veto legislation to ban abortion if Roe were overturned, Potts didn't hesitate: "I would veto it," he said.